As per the previous reviewers, this is indeed a wonderful example of ragtime playing and the instrumental combination is perfect! That said, I will state that the impressive 'riffs' you are hearing are coming from the mandolin, not the ukelele.

This is amazing! Mandolin and ukulele are such a perfect match, who would've known? Two great players did and prove it.

If you enjoyed this, definitely check out their medley of the Hawaiian song "Kuʻu ipo i ka heʻe puʻe one," provided by the good people at the UC-SB Cylinder Preservation & Digitization Project:

http://cylinders.library.ucsb.edu/search.php?queryType=@attr%201=1016&query=ukulele&num=1&start=1&sortBy=&sortOrder=id

If you want to hear someone just go nute on a ukelele, you've come to the right place as this guy GOES TO WORK on his ukelele taking the playing to new heights. I initially thought he was playing a banjo. The fact the this was a ukelele makes me that more impressed.